Full-circumferential flow pump

ABSTRACT

A full-circumferential flow pump has a circumferential fluid passage between a pump casing and a motor provided in the pump casing. The full-circumferential flow pump comprises a suction-side casing having a suction nozzle, and an outer cylinder connected to the suction-side casing and accommodating the canned motor therein. The suction-side casing and the outer cylinder have flanges, respectively extending radially outwardly from an open ends thereof. The adjacent flanges of the suction-side casing and the outer cylinder are clamped by clamping flanges to connect the suction-side casing and the outer cylinder.

This is a division of application Ser. No. 08/046,850 filed on Apr. 14,1993, now U.S. Pat. No. 5,388,971.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a full-circumferential flow pump havinga pump casing made of sheet metal, and more particularly to afull-circumferential flow pump having a pump casing which is made ofsheet metal such as stainless steel plate and formed by press working.

2. Description of the Related Art

It has been customary to press sheet steel such as stainless steel intoa pump casing according to a deep drawing process. The pump casing has acasing flange, at the open end thereof, which extends radially outwardlyand is formed integrally by press working. The casing flange has aplurality of bolt holes and is fixed to a holding member such as abracket using bolts passing through the bolt holes, thereby holding thepump casing. The pressed casing flange must meet mechanical strengthrequirements for bearing an internal pressure developed in the pumpcasing, and also rigidity requirements for keeping a sealing surfacestable. In conventional pressed pump casings, the casing flange has thesame thickness as the pump casing body.

Inasmuch as the pressed pump casing is of a relatively flexiblestructure, however, it is impossible for the casing flange itself tosatisfy both the mechanical strength requirements and the rigidityrequirements. To achieve a desired level of rigidity of the casingflange, the conventional pressed pump casings have employed a steelsheet whose thickness is greater than the thickness required towithstand an internal pressure developed therein, or a cylindricalreinforcing portion folded from the outer circumferential edge of thecasing flange and extending axially for reinforcing the casing flange,or a reinforcing member having a complex shape and made of the samematerial as the pump casing body.

As described above, the rigidity of the casing flange has been increasedby employing either a steel sheet whose thickness is greater than thethickness required to withstand an internal pressure developed in thepump casing, or a reinforcing portion at the outer circumferential edgeof the casing flange. The steel sheet of increased thickness is howeverdifficult to press to shape.

On the other hand, in case of providing a reinforcing member of complexshape results in an increase in the cost of manufacture of the pumpcasing.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide afull-circumferential flow pump having a pump casing made of ametal-sheet whose thickness is not greater than necessary to withstandan internal pressure developed in the pump casing, and which has noreinforcing portion or reinforcing member for reinforcing the casingflange.

According to one aspect of the present invention, there is provided afull-circumferential flow pump having a pump casing encasing a motordriving an impeller for pumping a fluid with a circumferential passageseparating the pump casing and an outer circumferential surface of themotor, the pump casing comprising: a suction-side casing made of sheetmetal and having a suction nozzle, the suction-side casing having aflange extending radially outwardly from an open end thereof; an outercylinder connected to the suction-side casing and accommodating themotor therein, the outer cylinder being made of sheet metal and having aflange extending radially outwardly from an open end thereof clampingflanges for clamping the adjacent flanges of the suction-side casing andthe outer cylinder so that the suction-side casing and the outercylinder are connected.

According to another aspect of the present invention, there is provideda full-circumferential flow pump having a pump casing encasing a motordriving an impeller for pumping a fluid with a circumferential passageseparating the pump casing and an outer circumferential surface of themotor, the pump casing comprising: a discharge-side casing made of sheetmetal and having a suction nozzle, the discharge-side casing having aflange extending radially outwardly from an open end thereof; an outercylinder connected to the discharge-side casing and accommodating themotor therein, the outer cylinder being made of sheet metal and having aflange extending radially outwardly from an open end thereof; clampingflanges for clamping the adjacent flanges of the discharge-side casingand the outer cylinder so that the discharge-side casing and the outercylinder are connected.

With the above structure, the pump casing including the suction-side anddischarge-side casings may be of a thickness just large enough towithstand an internal pressure developed therein, and does not need tobe reinforced by a special reinforcing portion or member. Accordingly,the pump casing can easily be pressed to desired shape, with the resultthat the pump casing can be produced with high productivity. As the pumpcasing requires no reinforcing member, the number of parts of the pumpcasing is relatively small, and the cost of the pump casing is low. Themaximum diameter of the pump casing becomes small to thus achievematerial-saving.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features, and advantages of the presentinvention will become apparent from the following description when takenin conjunction with the accompanying drawings which illustrate preferredembodiments of the present invention by way of example, wherein:

FIG. 1 is a cross-sectional view of a full-circumferential flow pumphaving a pump casing made of sheet metal according to a first embodimentof the present invention;

FIG. 2 is an enlarged detailed cross-sectional view of a pump casingshown in FIG. 1;

FIG. 3(a) is a cross-sectional view of a flange provided on an outercylinder shown in FIG. 1;

FIG. 3(b) is a side view of the flange provided on the outer cylindershown in FIG. 1;

FIG. 4 is a cross-sectional view of a pump casing with a mechanism forpreventing the casing from rotating according to the first embodiment ofthe present invention;

FIG. 5 is a cross-sectional view taken along line V--V of FIG. 4;

FIG. 6 is a cross-sectional view of a pump casing with a mechanism forpreventing the pump casing from rotating according to a modifiedembodiment of the present invention;

FIG. 7 is a cross-sectional view taken along line VII--VII of FIG. 6.

FIG. 8 is a cross-sectional view of a pump casing with a terminal boxaccording to a second embodiment of the present invention;

FIG. 9 is a cross-sectional view of a pump casing with a suction flangeaccording to a third embodiment of the present invention;

FIG. 10 is a cross-sectional view of a pump casing with a suction flangeaccording to a modified embodiment of the present invention;

FIG. 11 is a side view of the suction flange shown in FIG. 10;

FIG. 12 is a front view of a full-circumferential flow in line pump witha leg according to a fourth embodiment of the present invention;

FIG. 13 is a cross-sectional view of a full-circumferential flow in linepump shown in FIG. 12; and

FIG. 14 is a front view of a full-circumferential flow in line pump witha leg according to a modified embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A first embodiment of the present invention will be described below withreference to FIGS. 1 through 3.

FIG. 1 shows in cross section a full-circumferential flow in-line pumphaving a pump casing made of sheet metal according to an embodiment ofthe present invention. As shown in FIG. 1, the full-circumferential flowin-line pump generally comprises a suction-side casing 1, adischarge-side casing 5, and an outer cylinder 9 interconnecting thesuction-side casing 1 and the discharge-side casing 5. The suction-sidecasing 1, the discharge-side casing 5, and the outer cylinder 9 are inthe form of pressed sheets such as stainless steel. The suction-sidecasing 1, the discharge-side casing 5, and the outer cylinder 9 haverespective flanges 1a, 5a, 9a, 9b extending radially outwardly from openends thereof. The adjacent flanges 1a, 9a of the suction-side casing 1and the outer cylinder 9 are clamped by flanges 20A, 20B in the form ofcastings such as iron castings, and securely fastened to each other bybolts 37a and nuts 37b which join the flanges 20A, 20B. A resilient seal8 made of rubber or the like is interposed between the flanges 1a, 9a.Similarly, the adjacent flanges 5a, 9a of the discharge-side casing 5and the outer cylinder 9 are clamped by flanges 21A, 21B in the form ofcastings such as iron castings, and securely fastened to each other bybolts 37a and nuts 37b which join the flanges 21A, 21B. A resilient seal8 made of rubber or the like is interposed between the flanges 5a, 9b.The suction-side casing 1, the discharge-side casing 5, and the outercylinder 9 jointly serve as a pump casing made of sheet metal, whichhouses a canned motor 22.

The flanges 20A and 21A provided on the suction- and discharge-sidecasings are composed of integral member. The flanges 20A, 21A have arecess 20a, 21a, respectively in which the flanges 1a, 9a; 5a, 9b areaccommodated. When the flanges 20A, 20B and 21A, 21B are fastened witheach other, flange surfaces 20f, 21f thereof contact with each other.Thus, the interference of the resilient seal 8 is maintained at aconstant level in cooperation with the recesses 20a, 21a. Further, theflange 20A is fitted over the suction-side casing 1 by tight fit so thatthe flange 20A is not disengaged easily from the suction-side casing 1.Similarly, the flange 21A is fitted over the discharge-side casing 5 bytight fit so that the flange 21A is not disengaged easily from thedischarge-side casing 5.

Each of the flanges 20B, 21B is composed of two separable flange membersas shown in FIGS. 3(a) and 3(b). The flanges 20B, 21B are integrallyassembled when clamping the flanges 1a, 9a; 5a, 9b.

The suction-side casing 1 comprises a substantially cylindricalcup-shaped body 2 and an annular suction nozzle 3 extending axially intoa suction region from the cylindrical cup-shaped body 2. Similarly, thedischarge-side casing 5 comprises a substantially cylindrical cup-shapedbody 6 and an annular discharge nozzle 7 extending axially into adischarge region from the cylindrical cup-shaped body 6. The suctionnozzle 3 and the discharge nozzle 7 define respective suction anddischarge ports that are positioned axially in line with each other.

The full-circumferential flow in-line pump also has an inner casing 10disposed radially inwardly of the suction-side casing 1. The innercasing 10 comprises a partition plate 11 made of sheet metal at thesuction region and a guide device 12 which is connected to the partitionplate 11 and serves as guide vanes or a volute. The guide device 12 isfitted over a motor frame 23 of the canned motor 22 in asocket-and-spigot joint. The motor frame 23 of the canned motor 22 is ofa high rigid structure pressed from a sheet and the guide device 12 issupported on the motor frame 23 of the canned motor 22. As a result, theinner casing 10 is supported by the highly rigid motor frame 23 of thecanned motor 22. A resilient seal 14 is disposed between the innercasing 10 and the suction-side casing 1 to seal a suction side(low-pressure side) in the pump from a discharge side (high-pressureside) in the pump.

The full-circumferential in-line pump also has an impeller 15 rotatablydisposed in the inner casing 10. The impeller 15 is coupled to andsupported by a free axial end of a main shaft 16 coupled to the cannedmotor 22. A liner ring 19 is supported by the partition plate 11 of theinner casing 10, with a slight clearance defined between the liner ring19 and a suction-side axial end 15a of the impeller 15.

Suction and discharge flanges 31, 32 are fixed respectively to thesuction nozzle 3 and the discharge nozzle 7. Each of the suction anddischarge nozzles 3, 7 is made of the same material, such as stainlesssteel, as the pump casing, and has an externally threaded surface 3c, 7cand a front end surface 3s, 7s serving as a seal surface for mating withanother flange (not shown) to be coupled to the suction or dischargeflange. The suction and discharge flanges 31, 32 are made of a materialsuch as cast iron (FC) or the like, which is different from the materialof the pump casing, and have internally threaded surfaces 31a, 32a,respectively. Thus, the suction and discharge flanges 31, 32 arefastened to the suction and discharge nozzles 3, 7, respectively throughthreaded engagement.

In FIG. 2, the flange 20A (or 21A) comprises an integral member. In thecase where the inner diameter D_(A) of the flange 20A (or 21A) issmaller than the outer diameter D_(B) of the suction flange 31 (ordischarge flange 32), the flange 20A (or 21A) cannot be detached fromthe pump casing because of existence of the suction flange 31 (ordischarge flange 32). Therefore, the suction flange 31 (or dischargeflange 32) is detached from the suction nozzle 3 (or discharge nozzle 7)in the first plate, then the flange 20A (or 21A) is detached from thesuction-side casing 1 (or discharge-side casing 5). When assembling, theflange 20A (or 21A) is attached to the suction-side casing 1 (ordischarge-side casing 5), then the suction flange 31 (or dischargeflange 32) is attached to the suction nozzle 3 (or discharge nozzle 7).

The motor frame 23 of the canned motor 22 comprises a cylindrical frameouter barrel 24, frame side plates 25, 26 provided on both sides of theframe outer barrel 24. The frame outer barrel 24 has a plurality of ribs24a projecting radially outwardly from an outer circumferential surfacethereof. The ribs 24a are integrally formed with the motor frame outerbarrel 24 by embossing, and have outer surfaces fitted in andspot-welded or otherwise joined to the outer cylinder 9 of the pumpcasing.

One of the ribs 24a has a lead hole 24b through which leads of the motor22 extend. The leads also extend through an opening 9c defined in theouter cylinder 9 into a terminal box 38 that is fixed to the outercylinder 9.

The canned motor 22 has a stator 27 and a rotor 28 that are disposed inthe motor frame outer barrel 24. The rotor 28 is supported on the mainshaft 16 and disposed radially inwardly of the stator 27. A cylindricalcan 29 is fitted in the stator 27, which is fixedly positioned in themotor frame outer barrel 24. A bearing housing 31 is detachably fastenedto the frame side plate 25 with a resilient O-ring 30 being interposedbetween the bearing housing 31 and the frame side plate 25. The bearinghousing 31 and the frame side plate 25 are joined to each other by asocket-and spigot joint with a clearance fit with the O-ring 30 disposedtherein. A radial bearing 32 is supported by the bearing housing 31 tosupport a shaft sleeve 33 fitted over the main shaft 16.

A bearing housing 35 is detachably fastened to the frame side plate 26with a resilient O-ring 34 being interposed between the bearing housing35 and the frame side plate 26. The bearing housing 35 and the frameside plate 26 are joined to each other by a socket-and spigot joint witha clearance fit with the O-ring 40 disposed therein. The bearing housing35 is also prevented from being axially dislodged from the frame sideplate 26 by a holder plate 42 fixed to the discharge-side casing 5. Aresilient member 41 such as rubber is disposed in an axial gap betweenthe bearing housing 35 and the frame side plate 26. The bearing housing35 supports a radial bearing 36 on its radially inner surface and astationary thrust bearing 44 on its axially outer surface. A shaftsleeve 38 fitted over an opposite end portion of the main shaft 16 isrotatably supported by the radial bearing 36.

Two thrust disks 39, 43 are fixedly mounted to the opposite end portion,i.e., a discharge-side end portion, of the main shaft 16 in axiallysandwiching the bearing housing 35. The thrust disk 43 is rotatable withthe main shaft 16 and faces an axially inner end surface of the radialbearing 36 which provides a stationary thrust sliding surface. Thethrust disk 39 holds a thrust bearing 40 rotatable with the main shaft16 and facing an axially outer end surface of the stationary thrustbearing 44.

The full-circumferential flow in-line pump shown in FIGS. 1 through 3operates as follows: A fluid drawn from the suction nozzle 3 flowsthrough the inner casing 10 into the impeller 15. The fluid is thenradially outwardly discharged by the impeller 15, and directed by theguide device 12 to flow axially through an annular fluid passage 45radially defined between the outer cylinder 9 and the motor frame outerbarrel 24 of the canned motor 22. The fluid then flows from the passage45 into the discharge casing 5. Thereafter, the fluid is discharged fromthe discharge nozzle 7 that is connected to the discharge casing 5.

In the above embodiment, the suction-side casing 1, the discharge-sidecasing 5, and the outer cylinder 9 have respective flanges 1a, 5a, 9a,9b extending radially outwardly from open ends thereof. The adjacentflanges 1a, 9a of the suction-side casing 1 and the outer cylinder 9 areclamped by the flanges 20A, 20B, and securely fastened to each other bythe bolts 37a and the nuts 37b which join the flanges 20A, 20B.Similarly, the adjacent flanges 5a, 9b of the discharge-side casing 5and the outer cylinder 9 are clamped by the flanges 21A, 21B, andsecurely fastened to each other by the bolts 37a and the nuts 37b whichjoin the flanges 21A, 21B. The pump casing including the suction-sidecasing 1 and the discharge-side casing 5 may be of a thickness justlarge enough to withstand an internal pressure developed therein, anddoes not need to be reinforced by a special reinforcing portion ormember. Accordingly, the pump casing can easily be pressed to desiredshape, with the result that the pump casing can be produced with highproductivity. As the pump casing require no reinforcing member, thenumber of parts of the pump casing is relatively small, and the cost ofthe pump casing is low. The maximum diameter of the pump casing becomessmall to thus achieve material-saving.

Even if the pump casing is manufactured by stainless steel inconsideration of corrosion resistance, the flanges 20A, 20B, 21A, 21B donot need to use expensive stainless steel because they do not contactliquid to be pumped. Accordingly, the total cost for manufacturing apump is low. Further, the recesses 20a, 21a formed on the flanges 20A,21A for accommodating the flanges 1a, 5a, 9a, 9b prevent the pump casingfrom getting out of position by external force.

Next, a pump casing with a mechanism for preventing a pump casing fromrotating will be described in detail with reference to FIGS. 4 and 5.

As shown in FIGS. 4 and 5, the flange 20A is provided with a pin 50horizontally fixed thereon. The flange 1a of the suction-side casing 1has an outer periphery with a notch 1b. Similarly, the flange 9a of theouter cylinder 9 has an outer periphery with a notch 9d. The pin 50 isengaged with the notch 1b and the notch 9d, thus preventing thesuction-side casing 1 from rotating. The pin 50 is positioned in therecess 20a and does not project from the flange 20A, resulting in easyassembling.

FIGS. 6 and 7 show a pump casing with a mechanism for preventing a pumpcasing from rotating according to a modified embodiment of the presentinvention.

As shown in FIGS. 6 and 7, the flange 1a of the suction-side casing 1has an outer periphery with a notch 1b. Similarly, the flange 9a of theouter cylinder 9 has an outer periphery with a notch 9d. The fasteningbolt 37a for fastening the flanges 20A, 20B is engaged with the notch 1band the notch 9d, thus preventing the suction-side casing 1 fromrotating.

In the embodiments shown in FIGS. 4 through 7, the suction-side casing 1is shown and described, however the mechanism for preventing the pumpcasing from rotating is applicable to the discharge-side casing 5.

FIG. 8 shows a flange with a terminal box according to a secondembodiment of the present invention. In this embodiment, a flange 121Bis integrally provided with a terminal box 55. The flange 121B has suchstructure as a terminal box 55 is added to the flange 21B shown inFIG. 1. The terminal box 55 has an opening 55a into which a bush 56 isfitted. The tip end of the bush 56 is inserted into the opening 9c ofthe outer cylinder 9. Leads L are taken out of the canned motor 22through the lead hole 24b of the rib 24a and drawn into the terminal box55 through the bush 56. The terminal box 55 is covered with a lid 57. Agasket 58 is interposed between the outer cylinder 9 and the terminalbox 55 to prevent dew condensed onto the outer cylinder 9 from enteringthe terminal box 55 and the canned motor 22.

According to this embodiment, the terminal box 55 is not required to beattached to the outer cylinder 9 of the pump casing by welding or thelike. In this embodiment, the flange 121B provided on the outer cylinder9 adjacent to the discharge-side casing 5 is integrally provided withthe terminal box 55. However, a flange 20B provided on the outercylinder 9 adjacent to the suction-side casing 1 in FIG. 1 may beprovided with a terminal box.

FIG. 9 shows a suction flange according to a third embodiment of thepresent invention. In this embodiment, a suction-side casing 51 isintegrally provided with a suction nozzle 52. A suction flange 53 isfixed to a suction nozzle 52 through an intermediate ring 54. Theintermediate ring 54 is made of the same material, such as stainlesssteel, as the pump casing, and has a central opening 54a, an annularrecess 54b, and an externally threaded surface 54c. The intermediaterings 54 has a front end surface 54s serving as a seal surface formating with another flange (not shown) to be coupled to the suctionflange 53. The suction nozzle 52 has a smaller-diameter potion 52binserted into the opening 54a of the intermediate ring 54 and weldedthereto. The suction nozzle 52 also has a larger-diameter portion 52afitted in the recess 54b of the intermediate ring 54 in asocket-and-spigot joint and welded thereto. The suction flange 53 ismade of a material such as cast iron (FC) or the like, which isdifferent from the material of the pump casing, and has an internallythreaded surface 53a that is threaded over the externally threadedsurfaces 54c of the intermediate ring 54. Thus, the suction flange 53 isfastened to the intermediate ring 54 through threaded engagement.

According to this embodiment, the suction flange 53 is connected to thesuction nozzle 52 through the intermediate ring 54. The suction flange53 can be manufactured by the process other than press working to thusimprove its rigidity.

Even if the pump casing is manufactured by stainless steel inconsideration of corrosion resistance, the suction flange 53 does notneed to use expensive stainless steel because the flange 53 does notcontact liquid to be pumped. Accordingly, the total cost formanufacturing a pump is low.

FIGS. 10 and 11 show a suction flange according to a modified embodimentof the present invention. A suction-side casing of this embodiment isthe same as the suction-side casing 51 in FIG. 9. An intermediate ring64 connected to the suction nozzle 52 does not have an externallythreaded surface, but has an engaging portion 64c. The intermediate ring64 has a central opening 64a, an annular recess 64b and a front endsurface 64s. A suction flange 63 is composed of two separable flangemember 63A, 63B each having a semicircular ring shape as shown in FIG.11. Each of flange members 63A, 63B has an engaging surface 63a, 63bengageable with the engaging portion 64c of the intermediate ring 64shown in FIG. 10. According to this embodiment, the suction flange 63can be attached to the intermediate ring 64 after the intermediate ring64 is bonded to the suction nozzle 52. The intermediate ring 64 is madeof the same material such as stainless steel, as the pump casing. Thesuction flange 63 is made of a material such as cast iron or the like,which is different from the material of the pump casing. Referencenumerals 63c denote a bolt hole for fixing the suction flange 63 toanother flange (not shown).

In a flange structure shown in FIGS. 9 through 11, only a suction flangeis shown and described, however, this flange structure is applicable toa discharge flange as well.

Next, a full-circumferential flow pump having legs for supporting thepump will be described with reference to FIGS. 12 through 14.

As shown in FIGS. 12 and 13, a full- circumferential flow in-line pump Pis fixed to a base 81 through a suction flange 82 with a leg and adischarge flange 83 with a leg. The full-circumferential flow in-linepump P in FIGS. 12 has almost the same structure as thefull-circumferential flow in-line pump shown in FIG. 1, therefore theinterior structure of the pump will not be described.

The suction flange 82 has a female screw 82a, at the upper portionthereof, threaded with the intermediate ring 54, and a leg 82b extendingdownwardly and fixed to the base 81 as shown in FIG. 13. The dischargeflange 83 has a female screw 83a, at the upper portion thereof, threadedwith the intermediate ring 54, and a leg 83b extending downwardly andfixed to the base 81. The suction and discharge flanges 82 and 83 aremade of a material such as cast iron (FC) or the like, which isdifferent from the material of the pump casing.

In the above embodiment, external forces such as piping force aretransmitted to the suction and discharge flanges 82, 83, and then to thebase 81 through the legs 82a, 83a. Therefore, external forces such aspiping force are not transmitted to the suction- and discharge- sidecasings 1, 5.

FIG. 14 shows another embodiment of a full-circumferential flow pumphaving legs. As shown in FIG. 14, a full- circumferential flow in-linepump P is fixed to a base 81 through a flange 120A with a leg and aflange 121A with a leg. The full-circumferential flow in-line pump P inFIG. 14 has the same structure as the full-circumferential flow in-linepump shown in FIGS. 1 and 2. The flange 120A has such structure as a legis added to the flange 20A shown in FIGS. 1 and 2. That is, the flange120A has a flange body for clamping the flanges of the suction-sidecasing 1 and the outer cylinder 9, and a leg 120a extending downwardlyfrom the flange body and fixed to the base 81. Similarly, the flange121A has such structure as a leg is added to the flange 21A shown inFIGS. 1 and 2. That is, the flange 121A has a flange body for clampingthe flanges of the discharge-side casing 5 and the outer cylinder 9, anda leg 121a extending downwardly from the flange body and fixed to thebase 81.

Although certain preferred embodiments of the present invention havebeen shown and described in detail, it should be understood that variouschanges and modifications may be made therein without departing from thescope of the appended claims.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:
 1. A full-circumferential flow pump having a pumpcasing encasing a motor driving an impeller for pumping a fluid with acircumferential passage separating said pump casing and an outercircumferential surface of said motor, said pump casing comprising:anozzle provided on said pump casing, said pump casing being made ofsheet metal; a flange detachably mounted on said nozzle and having arigidity greater than that of said casing; and a seal surface providedon an axial end of said nozzle for mating with another flange to becoupled to said detachably mounted flange.
 2. The full-circumferentialflow pump according to claim 1, wherein said seal surface is formed onsaid nozzle.
 3. The full-circumferential flow pump according to claim 1,wherein said pump casing is made of corrosion resistant material.
 4. Thefull-circumferential flow pump according to claim 1, wherein saiddetachably mounted flange is mounted on said nozzle through threadedengagement.
 5. The full-circumferential flow pump according to claim 1,wherein said detachably mounted flange has a leg for supporting saidpump casing.
 6. The full-circumferential flow pump according to claim 1,wherein said detachably mounted flange comprises separable members. 7.The full-circumferential flow pump according to claim 1, furthercomprising an intermediate ring interposed between said nozzle and saiddetachably mounted flange, wherein said seal surface is formed on saidintermediate ring.
 8. The full-circumferential flow pump according toclaim 7, wherein said intermediate ring is made of corrosion resistantmaterial.
 9. The full-circumferential flow pump according to claim 7,wherein said detachably mounted flange is mounted on said intermediatering through threaded engagement.